Earth's Scars: Exploring the World's Five Great Rift Systems

3. The Mid-Atlantic Ridge: An Underwater Mountain Range

The Mid-Atlantic Ridge is one of the most broad geological formations on Earth hidden under the Atlantic Ocean. Comprising more than 16,000 kilometres, this undersea mountain range snakes from the Arctic Ocean to the southern tip of Africa. The Mid-Atlantic Ridge, a divergent tectonic plate boundary, shows where the North American and Eurasian plates in the north and the South American and African plates in the south are progressively separating. About 180 million years ago, as the supercontinent Pangaea started to split, the Mid-Atlantic Ridge started to form. Magma from the Earth's mantle rose to cover the progressively separating tectonic plates, generating fresh oceanic crust. With fresh crust created at roughly 2.5 cm year, this process—known as seafloor spreading—is still under way today. The continual building of fresh crust at the ridge drives the current of the continents and forms the Atlantic Ocean basin by pushing the old crust outward. Though primarily buried under the waters, the Mid-Atlantic Ridge does surface in a few areas, most famously Iceland. Here the volcanic activity of the ridge has produced a distinctive scene of geysers, hot springs, and spectacular lava fields. Basically a large volcano, the island is always expanding over the divergent barrier. The exposed sections of the ridge give researchers great chances to investigate plate tectonics and the mechanisms sculpting the surface of our planet, therefore providing a window into the strong forces operating far down within the Earth.